The disclosed invention is generally directed to rectifying power supplies, and is more particularly directed to a high frequency rectifying power supply which does not utilize a complex transformer.
Rectifying power supplies are utilized in certain applications where the required supply voltage is DC. The originating power source may provide an AC voltage or a DC voltage. With a DC voltage supply, stepping the voltage up or down requires conversion of the DC power to AC power which may be accomplished, for example, with a square wave converter or a sinewave converter. Typically, the AC voltage is generally stepped up or stepped down as required by a transformer, and then rectified.
Significant improvements in the size and weight of rectifying power supplies have been made by increasing the operating frequency of the AC power. Particularly, higher operating frequencies allow for significantly smaller capacitive elements. However, operating frequencies have been limited by certain considerations including the increase of transformer size with frequency, and the inability of known transformer designs to operate at frequencies greater than one MHz. Particularly, with increased AC operating frequencies, transformer isolation is reduced, reflections increase, and core losses increase. As a result of problems encountered with increased frequencies, different transformer designs have been made in attempts to allow for higher AC operating frequency operation. Such designs, however, are complex and generally require time-consuming and costly development for particular applications. Moreover, such transformer designs do not provide significant increases in AC operating frequencies, and moreover are bulky.
A further consideration in the implementation of high frequency power supplies is the power handling limits of available diodes. If the number of secondary windings is reduced in attempting to make transformers smaller and less complex, then the power limits of available diodes may be exceeded. If more secondary windings are used to accommodate the power limits of available diodes, then transformer complexity and size increase.